Translation of the Report



Chief Rolling Engineer

M.A. Babenko





of industrial testing of mill rolls (the set 42p-66) hardened by the method of discrete coating implemented in the NIR (scientific research project) with the private research and manufacturing company "Tavi", agreement No 4224 of 28.08.03


On 29.12.03, to the 8th stand MC 250-3 there was mounted a set of rolls 42p-66 (350 mm in diameter) bored out with 6 calibres to roll the rhomb 40 x 6 mm.

The 1st calibre (numerated from the input) has not been hardened, 2nd and 3rd calibres have been hardened by microplasma coating, and 4-6th calibres have been hardened by discrete coating.

The rolling was began with the 5th calibre; it was in operation 3 days from 29.12.03 to 1.01.04 and rolled 3754 tons without any claims. Then we transited to the 6th calibre.

The 6th calibre was in operation 2 days from 1.01.04 to 3.01.04 and rolled 2238 tons; a longitudinal crack has been revealed on both rolls; then we transited to the 4th calibre.

The 4th calibre was in operation 3 days from 3.01.04 to 6.01.04 and rolled 3115 tons.

Having measured with the template the wear-out of 5th calibre, we decided as an experiment to put this calibre into further operation. The calibre was in operation from 6.01.04 to 7.01.04 and rolled additionally 1470 tons. Totally this calibre has rolled 5224 tons.

After this additional work of 5th calibre, we transited to the 1st calibre; it was in operation 2 days from 7.01.04 to 9.01.04 and rolled 1916 tons.

2nd calibre (that worked from 9.01.04 to 11.01.04) has rolled 1904 tons.

3rd calibre (that worked from 11.01.04 to 13.01.04) has rolled 1670 tons.

After this set has completed its term, we have measured the wear-out of calibres, see the sketches of wear-out in the appendix.

The maximal wear-out of 4th, 5th and 6th calibres hardened by the discrete coating was -1,0 mm, and on the 1st, 2nd and 3rd calibres not hardened by the discrete coating it amounted -1,5 mm. Thus, calibres hardened by the discrete coating have been worn out 0,67 times less, and the large grid of carbon deposit is absent on them.

The maximal value of resistance of calibres hardened by discrete coating amounted 5224 tons. Maximal value of resistance of non-hardened calibres was 1916 tons.

5224 tons : 1916 tons = 2,77 times,

i.e., the maximal resistance of calibre hardened by discrete coating is 2,77 times higher than maximal resistance of calibres that were not hardened by this technique.

Proceeding from the carried out testing and above calculation, we made the following conclusion:

  • the experimental calibres hardened by the suggested technique have an uniform wear-out;

  • during the operation time, the calibres wear out in proportion to the amount of rolled metal;

  • the maximal resistance of these calibres is 2,77 times more than that of calibres without this coating;

  • the surface of experimental calibres after operation has less grid of carbon deposit.

Deputy chief of SPC-1 in technologies (signature, 28.01.04)

Senior master of MC-3 (signature, 28.01.04)

Chief of LPV (signature, 28.01.04)

Engineer of LPV (signature, 28.01.04)                        

N.P. Bely

A.R. Shikerin

S.V. Demichev

O.A. Zaytzev


Set 42p - 66

1st calibre, not hardened

Rolled 1916 tons

fig1a.gif (2686 bytes)

2nd calibre, microplasma hardening

Rolled 1904 tons

fig2a.gif (2685 bytes)

3rd calibre, microplasma hardening

Rolled 1670 tons

fig3a.gif (2685 bytes)

4th, 5th, and 6th calibres with discrete hardening

4th calibre

Rolled 3115 tons

fig4a.gif (2693 bytes)

5th calibre

Rolled 5224 tons

fig5a.gif (2688 bytes)

6th calibre

Rolled 2238 tons

fig6a.gif (2704 bytes)

Scanned original in Russian

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